Home Forums SYSTEM Hierarchical Modulation

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    • #41388
      Tayyab Mehmood
      Participant

      Hi, I am trying to do QPSK/16QAM Hierarchical modulation with High-priority (HP) QPSK signals and the Low-priority (LP) 16 QAM signals. But unable to add them to see them on a single constellation diagram (as shown in the conceptual diagram).
      I have attached the optisystem file along with the conceptual figure too.
      Thanks

    • #41390
      Tayyab Mehmood
      Participant

      Here is the basic conceptual diagram of hierarchical modulation in the electrical domain

      Attachments:
    • #41830
      preben
      Participant

      Hi,Tayyab,

      do you solve your problem? I am also interested in this kind modulation in OptiSystem.

    • #41831
      Tayyab Mehmood
      Participant

      Still, did not find a solution to do hierarchical modulation in Optisystem 14.0. But succeeded to do hierarchical modulation in MATLAB.

    • #41875
      Damian Marek
      Participant

      I put this small project together to demonstrate how to do it in OptiSystem. It’s not too hard.

      One of the signals is the underlying signal which is amplified by 2 and the extra signal is layered on top in each quandrant.

      Regards,
      Damian

    • #41878
      Tayyab Mehmood
      Participant

      Thanks Damian for replying with such a helpful material. I have done this part too in the optisystem. I am wondering how one can extract both the signals (high priority and low priority) at the receiver side . Would you please help me in this regard.

      • #41879
        Damian Marek
        Participant

        You could make a 4 QAM Demodulator to get back the primary signal. The demodulator should be made so that it does not care about the detailed parts in each quadrant, but simply detects which quadrant the symbol is in. That would give back the first signal.

        For the second it would also be a 4 QAM demodulator but with its constellation shifted into one of the quadrants. Just make a user defined IQ map.

        +1
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